Last update issued on October 7, 2003 at 03:00 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update October 4, 2003)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 4, 2003)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 4, 2003)]
[Historical solar and geomagnetic data charts 1954-2003 (last update July 23, 2003)]
[Archived reports (last update October 7, 2003)]
The geomagnetic field was quiet to unsettled on October 6. Solar wind speed ranged between 368 and 734 km/sec. The main part of the fairly weak high speed stream from coronal hole CH61 was observed at ACE after 11h UTC with solar wind speed peaking at 22h UTC.
Solar flux measured at 20h UTC on 2.8 GHz was 112.1. The planetary A
index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.8).
Three hour interval K indices: 22223333 (planetary), 21113334 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight there were 4 spotted regions on the visible disk. Solar flare activity was very low.
Region 10471 developed slowly in the southwestern part. The magnetic delta structure disappeared and the region became
fairly quiet. Some increase in activity was noted late in the day.
Region 10473 was quiet and stable.
New region 10476 emerged in the southeast quadrant-
New region 10477 rotated into view at the southeast limb.
October 4-6: No potentially geoeffective CMEs observed.
Coronal hole history (since late October 2002)
Compare today's report with the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A coronal hole (CH61) in the northern hemisphere and with a trans equatorial extension was in a geoeffective position on October 3-4.
Processed SOHO/EIT 284 image at 23:30 UTC on October 6. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to active on October 7 due to a high speed stream from coronal hole CH61. Quiet to unsettled is likely on October 8-11.
Long distance low frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along north-south paths is fair to good. [Trans Atlantic propagation conditions are currently monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay, at least 3 stations from Brazil could be heard at times as well. Radio Sarandi del Yi (Uruguay) on 1550 kHz was the most interesting station on other frequencies].
|Coronal holes (1)||Coronal mass ejections (2)||M and X class flares (3)|
1) Effects from a coronal hole could reach Earth within the next 5 days.
2) Material from a CME is likely to impact Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 hours.
Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.
Compare to the previous day's image.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SEC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SEC or where SEC has observed no spots.
|Solar region||Date numbered||SEC
|Location at midnight||Area||Classification||Comment|
classification was CSO
classification was HRX
classification was HAX
|Total spot count:||43||45|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2003.04||126.4||60.0||(69.6 predicted, -4.5)|
|2003.05||115.7||55.2||(65.3 predicted, -4.3)|
|2003.06||129.3||77.4||(61.5 predicted, -3.8)|
|2003.07||127.7||85.0||(58.0 predicted, -3.5)|
|2003.08||122.1||72.7||(55.0 predicted, -3.0)|
|2003.09||112.2||48.8||(53.0 predicted, -2.0)|
|2003.10||120.4 (1)||19.0 (2)||(50.3 predicted, -2.7)|
1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (NOAA/SEC) sunspot number. The official international sunspot number is typically 30-50% less.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from sources noted in solar links. All time references are to the UTC day. Comments and suggestions are always welcome.